Surgical patients undergoing major procedures and general anaesthesia face several consequences during and following the operation. Keeping the body temperature of a patient within normal limits is an important goal while in the operating room. Likewise, prevention of post-operative pressure ulcers requires addressing the patient's skin pressures during their immobilised state.
There are currently products available to provide warming to patients who are undergoing surgery and who are under anaesthesia. These have limitations to the surgeon and patient.
One type of conventional heater system which is currently available is similar to a normal electric-blanket for a bed. Such heater systems are placed under the patient between the patient and the mattress to allow for an efficient heat transfer. However, these systems are not compatible with the use of dynamic pressure-relieving mattress systems such as the Talley Quattro range of products available from Talley Group Limited of Abbey Park Industrial Estate, Premier Way, Romsey, Hampshire SO51 9DQ, United Kingdom.
Dynamic pressure-relieving mattress systems of this kind are intended to alleviate the possibility of pressure sores by having an inflatable mattress with a number of separate inflation chambers that are inflatable independently of one another to a desired inflation pressure. Generally, each inflation chamber includes a respective plurality of mutually spaced inflatable cells. For example, FIG. 1 is a schematic representation of such an inflatable mattress 10 including a number of inflation cells 12 which are arranged to form four separate inflation chambers 12a, 12b, 12c and 12d. The inflatable mattress 10 is elongate in direction y. The inflation cells 12 are each elongate in orthogonal direction x and are arranged side by side (at different y coordinates) so as to extend widthways across the mattress 10.
In use, a pump and control unit 14 is connected to the mattress 10 via four separate air hoses 16a, 16b, 16c and 16d. In FIG. 1, hoses 16a and 16b are schematically shown as solid lines and hoses 16c and 16d are schematically shown as dashed lines. The hoses 16 are used to independently vary the inflation pressure of each inflation chamber over time. For example, in a particular mode of operation, the second, third and fourth inflation chambers 12b, 12c and 12d will initially be inflated, with a reduced pressure in the inflation cells of the first inflation chamber 12a. After a specified time period, the configuration will change such that the first inflation chamber 12a will be inflated and the pressure in the second inflation chamber 12b will be reduced. Next, the second inflation chamber 12b will be inflated and the pressure in the third inflation chamber 12c will be reduced. And, finally, the third inflation chamber 12c will be inflated and the pressure in the fourth inflation chamber 12d will be reduced. The pump and control unit 14 continually cycles through these four configurations such that, at any given time, the patient is only supported by 75% of the load-bearing upper surface of the mattress 10. This helps to prevent pressure sores by relieving interface pressure against a patient's soft tissue when immobilized for extended time periods, for instance during extended surgical operation procedures. Further details regarding dynamic pressure-relieving mattress systems are given in EP 0,732,886 in the name of Talley Group Limited.
The conventional electric-blanket-like heater systems mentioned above are not suitable for use with dynamic pressure-relieving mattress systems because the contact surface between the patient and the mattress is modified from being a stretch material (of the dynamic pressure-relieving mattress) to a non-stretch material or material with reduced-stretch characteristics (of the heater system). Therefore long surgical procedures (which could be as long as 20 hours) can cause the onset of serious pressure sores as the patient is immobilised for such a long period.
Other heater systems are known in which a light gown or cover is placed over the patient, and warm air is blown over the patient beneath the overlying cover or gown. Such heater systems only allow warming of the patient from their top side and limit the accessibility of the patient to the surgeon.
The present invention seeks to provide an alternative system which provides various advantages over those of the prior art. In particular, the present invention aims to provide an effective patient heating system which is compatible with the use of a dynamic pressure-relieving mattress system.